Development and implementation of the lung volume reduction pulmonary rehabilitation tool to identify eligibility for lung volume reduction in people with chronic obstructive pulmonary disease during pulmonary rehabilitation.

BACKGROUND: Completion of pulmonary rehabilitation is recognised in chronic obstructive pulmonary disease (COPD) guidelines as a key opportunity to consider systematically whether a respiratory review to assess potential suitability for a lung volume reduction (LVR) procedure might be appropriate. We describe the development of a simple decision-support tool (the LVR-PR tool) to aid clinicians working in pulmonary rehabilitation, to operationalise this process. METHODS: We took an iterative mixed methods approach, which was partnership-based and involved an initial consensus survey, focus groups and an observational study cohort at multiple pulmonary rehabilitation centres. RESULTS: Diagnosis (97%), exercise capacity (84%), breathlessness (78%) and co-morbidities (76%) were acknowledged to be essential items for assessing basic LVR eligibility. Collating prior investigations and assessing patient understanding were considered useful but not essential. Clinician concerns included; streamlining the tool; access to clinical information and investigations; and care needed around introducing LVR therapies to patients in a PR setting. Access to clearer information about LVR procedures, the clinician's role in considering eligibility and how educational resources should be delivered were identified as important themes from patient group discussions. The LVR-PR tool was considered to be feasible and valid for implementation in a variety of PR services across the UK subject to the provision of appropriate health professional training. Clinicians working in specialist LVR centres across the UK who were not otherwise involved in the development process confirmed the tool's validity using the content validity index (CVI). INTERPRETATION: The LVR-PR tool appears to be an acceptable tool that can be feasibly implemented in PR services subject to good quality educational resources for both patients and healthcare professionals.

Reproducibility of 19 F-MR ventilation imaging in healthy volunteers.

PURPOSE: To assess the reproducibility of percentage ventilated lung volume (%VV) measurements in healthy volunteers acquired by fluorine (19 F)-MRI of inhaled perfluoropropane, implemented at two research sites. METHODS: In this prospective, ethically approved study, 40 healthy participants were recruited (May 2018-June 2019) to one of two research sites. Participants underwent a single MRI scan session on a 3T scanner, involving periodic inhalation of a 79% perfluoropropane/21% oxygen gas mixture. Each gas inhalation session lasted about 30 seconds, consisting of three deep breaths of gas followed by a breath-hold. Four 19 F-MR ventilation images were acquired per participant, each separated by approximately 6 minutes. The value of %VV was determined by registering separately acquired 1 H images to ventilation images before semi-automated image segmentation, performed independently by two observers. Reproducibility of %VV measurements was assessed by components of variance, intraclass correlation coefficients, coefficients of variation (CoV), and the Dice similarity coefficient. RESULTS: The MRI scans were well tolerated throughout, with no adverse events. There was a high degree of consistency in %VV measurements for each participant (CoVobserver1 = 0.43%; CoVobserver2 = 0.63%), with overall precision of %VV measurements determined to be within ± 1.7% (95% confidence interval). Interobserver agreement in %VV measurements revealed a high mean Dice similarity coefficient (SD) of 0.97 (0.02), with only minor discrepancies between observers. CONCLUSION: We demonstrate good reproducibility of %VV measurements in a group of healthy participants using 19 F-MRI of inhaled perfluoropropane. Our methods have been successfully implemented across two different study sites, supporting the feasibility of performing larger multicenter clinical studies.

Emphysematous changes and normal variation in smokers and COPD patients using diffusion 3He MRI.

INTRODUCTION: This study aims to quantify global and regional changes of diffusive motion of 3He gas within the lung, as determined by hyperpolarized 3He MR apparent diffusion coefficient (ADC) measurement, in non-smokers, smokers and chronic obstructive pulmonary disease (COPD) patients. METHODS: Age-matched groups of six healthy non-smokers, five healthy smokers and five patients with COPD. The experiments were performed with approval from the local Research Ethics Committee. Diffusion imaging was performed following hyperpolarized 3He gas inhalation, producing ADC maps. Mean and standard deviation of the ADCs were used to compare the subject groups and assess regional variations within individuals. RESULTS: The intra-individual standard deviation of ADC in the healthy smokers was significantly larger than that of the non-smoking group (P < 0.02). Compared to the non-smoking group, COPD patients had significantly higher mean and standard deviation of ADC (P < 0.01). The mean ADC in the anterior half of the chest was systematically higher than in the posterior half in the healthy non-smoking subject group. DISCUSSION: This study suggests that there are regional trends in the ADC values of healthy volunteers that may have implications for the clinical interpretation of ADC values. Less homogeneous ADC values have been detected in asymptomatic smokers, indicative of damage to the distal air spaces.